#库的使用

#删除指定文件
import os
# os.remove('readme')

#打印指定模块中的函数名和变量名
# names = dir(os)
# for name in names:
#     print(name)

#使用日期模块
import datetime

# date1 = datetime.datetime(2023,11,3)
# date2 = datetime.datetime(2023,11,2)
# print(date1-date2)

# def reverse_word(s:str):
#     tokens = s.split(' ')
#     tokens.reverse()
#     return ' '.join(tokens)
# #函数中的参数是形参，不会改变当前的str
# str = 'I am a student.'
# print(str)
# print(reverse_word(str))


#统计一个字符是否能通过旋转的操作变成另外一个字符
# def rotate_string(str,goal):
#     if len(str) != len(goal):
#         return False
#     return goal in (str+str)
# str = 'abcde'
# target = 'bcdea'
# tmp = 'nihao'
# print(rotate_string(str,target))
# print(rotate_string(str,tmp))


# def count_prefix(words:list,s:str):
#     count = 0
#     for word in words:
#         if s.startswith(word) :
#             count += 1
#     return count


